The hydrogen-bonding geometry in carbohydrate crystals will be studied by neutron or low-temperature X-ray diffraction in those structures where existing data indicate that there is a range of different O-H...O interactions, such as have been observed in some methyl-alpha-pyranosides. The influence of the acetal conformations in pyranose sugars on hydrogen-bond formation will be examined by means of ab-initio quantum mechanical calculations in collaboration with Dr. Marshall Newton. We hope to discover whether there is any theoretical basis for the observation that hydrogen bonds from anomeric hydroxyl groups tend to be shorter than the average values for the type of interaction involved. The research will continue on the order/disorder properties of mixed crystals of alpha and beta anomers with special reference to alpha, beta-maltose and alpha,beta-melibiose. The puckering parameters and ring torsion angles in known pyranose compounds will be examined to see whether these structural parameters can be correlated with the strain effects which might arise from different types of intermolecular hydrogen-bond arrangements. BIBLIOGRAPHIC REFERENCES: Bibliography of Crystal Structures of Carbohydrates, Nucleosides and Nucleotides (1973) G.A. Jeffrey and M. Sundaralingam Adv. Carbohydr. Chem. Biochem. 31, 347-369 (1975). A Neutron Diffraction Refinement of the Crystal Structure of 1-O-Methyl alpha-D-altropyranoside B.J. Poppleton, G.A. Jeffrey and G.J.B. Williams Acta Cryst. B31, 2400-2404 (1975).